Utilities often have to cope with the problem of satisfying consumer demand for energy. Energy demands fluctuate widely between peak and off-peak periods. For example, energy demands peak during hot summer days when consumers require air conditioning. One of the ways utilities handle such situations is by employing load management systems. Information is communicated between subscribers and a headend to efficiently manage consumer energy demands.
Other energy services have been developed including utility-based applications such as water, gas, and electric meter readings. In these applications, the headend communicates with a meter at a subscriber's premises. Often subscribers want to know what their energy cost and usage are at a particular time, for example during a billing period. An existing utility application allows the subscriber to request this information from the utility. The utility first obtains the information from the meter at the subscriber's premises performs a calculation at the headend and transfers the desired information to the subscriber.
More and more applications have been developed including those which extend beyond conventional utility applications. For example, home security and monitoring and the ability to program appliances are applications which can be implemented. These applications are distributed by different companies which use different protocols for both implementation of their services and for compatibility with the devices located on the subscriber premises.
Existing systems for communicating utility applications are closed or proprietary systems which require a specific type of native message compatible with devices located on the subscriber premises. For example, the applications are distributed over a wide area network that is specifically designed to handle the protocol for a particular vendor's application and the device located at the subscriber's premises.
There is a need to provide a network distribution system in which applications having different protocols can be broadcast together over the same network.
Another problem exists in setting up a scheme for a two-way interactive network distribution system wherein information can be transmitted in an inexpensive, orderly and an efficient manner between the headend and downstream gateways. One of the ways to control data transmission between gateways and the headend is for the gateway to be programmed to receive and transmit at specific times using a TDMA (time division multiple access) scheme. Existing TDMA schemes provision the gateway to operate stand alone. Thus, the gateway must keep track of when to talk and when to listen. These functions require processing power and are expensive to implement. As a result, existing schemes require significant processing power at the gateway because intelligence must be incorporated to provision the gateway for stand alone operation. Thus, there is a need to reduce the amount of intelligence in the gateway to limit the overall system cost and processing power required by the gateway.